Sigma Mini Wide II 28mm F2.8

!Karen · Joined: 20 Jul 2013 Posts: 837 Location: Belgium Baby

FD mount

Sorry guys, all close ups.

I discovered today while playing with my FD 24mm that my adapter doesn't reach infinity! I never noticed this before because untill today I never used a wide angle FD on a nex Sad

I checked infinity focus with the sigma mini wide lens and it's no better making me conclude it is in fact the adapter's fault. Suggestions for a new FD - NEX adapter are welcome.

So while the sigma was on the camera I just shot some pictures with it. It can focus very close at 22cm.

All wide open.

DigiChromeEd · Joined: 29 Dec 2009 Posts: 3462 Location: Northern Ireland

Karen, I'm confused. Are these shots from the Sigma as stated in your title or from the Canon?

!Karen · Joined: 20 Jul 2013 Posts: 837 Location: Belgium Baby

from the sigma! Smile

pdccameras · Expire: 2014-08-11

HI Karen,

Beautiful close-ups by the way! Before you give up on your adapter, you may be able to fix it without a whole lot of effort. Most likely the adapter isn't too far off. I usually find I have to "accurize" most of my adapters. If the lens is not focusing to infinity, the lens is being pushed too far away from the camera as if you were using extension tubes. The general way I fix this problem is to remove the lens flange and remove some material from the back, allowing the lens to fit closer to the camera.

If your adapter looks like my FD -> NEX adapter, it isn't too hard to fix up. Here is mine:

Now, assuming you have a similar adapter, find a nice, solid, flat table or bench to work on. Here is all you'll need: small screwdriver, some fine emery cloth, and the adapter.

Next, make a pencil mark on the outside case of the adapter where the red index mark is, so you can put the lens flange back on in the same orientation it was before you started.

Now remove the three small screws that hold the lens flange to the adapter, store the screws away safely, and pull the flange off the adapter.

Next, with a firm, even pressure, rub the back of the lens flange on the emery paper in a smooth circular motion. This part will take some time, some effort and some trial and error. Periodically check the back of the flange to make sure that you are removing material evenly. Also take some time to blow away the metal filings every once in a while. After you have been rubbing for about 10 - 15 minutes, reassemble the adapter and try infinity focus with your lens. Repeat the process until infinity focus is achieved! Best of luck!!! Paul

DigiChromeEd · Joined: 29 Dec 2009 Posts: 3462 Location: Northern Ireland

Nice results, Karen. I have this lens but have never used it for close-ups.

!Karen · Joined: 20 Jul 2013 Posts: 837 Location: Belgium Baby

Paul,

Thank you so much for the very detailed info and the pictures to illustrate. I have been having a go at this for a bit today but so far infinity is not yet attained so I am filing some more tomorrow. But I won't be able to go much further anymore, or I also need to start taking off material from the open-lock ring as well. Otherwise the lens flange will 'sink' too far into the adapter and the lens can no longer be put on.

There is also another issue with the adapter, it does not stop the lens down as it should. It goes to around f11 and then it is unable to close the aperture any further. But this is not such a big issue, I hardly ever use smaller apertures anyway.

Seems I bought very crappy one Smile

pdccameras · Expire: 2014-08-11

Hi Karen,

It does sound like you got a pretty bad one! I have never had any that were more than a fraction of a mm off. The EBay seller Rainbow imaging has some pretty good ones!

best of luck!

Paul

RAART · Posted: Wed Apr 23, 2014 6:17 am Post subject:

I have the same lens but for some reason I think that my lens has different color rendering then this one here. I have to take some pictures and compare them but no time now.

RAART · Posted: Thu May 01, 2014 6:24 pm Post subject:

A quick question for anyone who uses Pentax cameras with 28mm Sigma Mini-WideII Multi Coated lens. On my Pentax K-5II this lens always need adjustments -1 to -2 depending on the photographer preference. I do not know why the camera always overexpose the images taken with Sigma lens. When I have Pentax-A lens attached the exposure is always perfect but not with Sigma Mini-Wide II, though the Sigma is also P-KA mount (have A setting) that should communicate with camera and it does but as I stated always overexposed.

Any comments on this? Other than that the lens is in excellent condition, optically and cosmetically.

Dogtag · Joined: 27 Jul 2013 Posts: 166 Location: Holland del norte

!Karen · Joined: 20 Jul 2013 Posts: 837 Location: Belgium Baby

Just a little update on the adapter issue: I gave the ring to my dad and he used some heavy machinery to get the job done and it does seem to focus to infinity now! Me happy. Didn't know it was this simple to modify them, thanks again for the explenation, Paul!